43.American Idiot

Original Broadway cast: John Gallagher Jr. as Johnny, Michael Esper as Will, Mary Faber as Heather, Rebecca Naomi Jones as Whatsername, Christina Sajous as The Extraordinary Girl, Stark Sands as Tunny, Tony Vincent as St. Jimmy

Performance dates: April 20, 2010-April 24, 2011

What it's about: Johnny, Will, and Tunny are three disaffected youths living in Jingletown, USA. While Johnny and Tunny escape to the city, Will is forced to stay behind with his pregnant girlfriend Heather. The city offers new thrills, but Johnny falls into drug abuse and Tunny is recruited and enlists in the army.

Why it's essential: There were rock musicals before American Idiot, but few were as effective at capturing the raw energy that infuses the show. Although the music isn't original, it's transformed in its theatrical context. Like the album on which it's based, American Idiot feels like a time capsule of Bush-era rage and ennui.

What it's about: Based on the 2001 film of the same name, Legally Blonde follows Elle Woods, a sorority girl who gets dumped by her boyfriend Warner and ends up following him to Harvard Law School to win him back. She turns out to be adept at the law and ends up defending a woman falsely accused of murder.

Why it's essential: It may not be the deepest musical, but Legally Blonde — like Elle Woods — deserves credit for what it does well. The show is just fun, a pitch-perfect adaptation of the similarly delightful film, and it was the ideal showcase for the bubbly talents of Laura Bell Bundy.

What it's about: A young man in San Francisco finds an old diary belonging to Stu, who writes about being drafted to fight in World War II back in 1943. Among his fears about combat, Stu has to confront his feelings for fellow soldier Mitch. Working as a photographer for Yank Magazine, Stu discovers a hidden gay world.

Why it's essential:Yank!, which was first performed as a workshop in 2005, was revived off-Broadway in 2010, a time at which DADT was very much part of the national conversation. The music and style evoke a classic 1940s musical, but the timeless themes and military context made it relevant for a modern-day audience.

What it's about: Based on Tolstoy's War and Peace — or rather, one section of the epic Russian novel — Natasha, Pierre & the Great Comet of 1812 sees the titular Natasha romanced by Anatole in 19th century Moscow high society. Complicating matters, Pierre also has eyes for Natasha, much to his despair.

Why it's essential: A musical based on War and Peace is already a tough sell, but add to that the fact that Natasha, Pierre & the Great Comet of 1812 is performed in a tent while the audience eats and drinks, making this an impressively immersive show. Thoroughly unique experiences like this one are few and far between.

39.Once

Joan Marcus

Book: Enda Walsh

Music and lyrics: Glen Hansard and Markéta Irglová

Original Broadway cast: Steve Kazee as Guy, Cristin Milioti as Girl, David Abeles as Eamon, Will Connolly as Andrej, Elizabeth A. Davis as Réza, David Patrick Kelly as Da, Anne L. Nathan as Baruška, Lucas Papaelias as Švec, Andy Taylor as Bank Manager

Performance dates: March 18, 2012-

What it's about: A stage adaptation of the 2006 musical film, Once is about an unnamed man and woman who form a musical partnership and fall in love over a few days in Dublin. Sadly, Guy, an unsuccessful busker, and Girl, a Czech immigrant, are both involved with other lovers, and their brief affair goes unconsummated.

Why it's essential: Today's Broadway loves musical adaptations of films, but Once stands out from the rest. It's a hauntingly bittersweet show made all the more memorable by its intimate staging, including the stage doubling as a bar during intermission. Like the film, its power lies in being an untraditional love story.

What it's about: Like the classic 1956 film, Giant is an expansive story based on Edna Ferber's 1952 novel. It begins in 1922, with cattleman Bick marrying Leslie. Also in love with Leslie is Jett, a handyman who discovers oil on his own. The story covers decades of shifting relationships and changing ideals.

Why it's essential:Giant tests the limits of how long a musical can be, clocking in at an impressive three hours and 45 minutes. Originally presented in three acts, Giant may simply be too much for some, but the show's length aptly reflects the expansiveness of the plot and of the Texas setting. It's called Giant for a reason.

What it's about: A musical adaptation of the 1923 Elmer Rice play, an Expressionist classic, Adding Machine is a bit hard to describe. Antihero Mr. Zero learns he has been replaced by an adding machine after 25 years of work, so he kills his boss in revenge. He is tried for murder and hanged — but that's not the end.

Why it's essential: It's fitting that an odd Expressionist play would become an odd Expressionist musical. Adding Machine represents the kind of unconventional theater that can find a comfortable home off-Broadway. And the theater community takes notice — the show won the Lucille Lortel Award for Outstanding Musical.

What it's about: The semi-autobiographical A Class Act reflects on the life and work of composer-lyricist Edward Kleban by those who knew him. The musical begins with a 1988 memorial service for Kleban, then moves backward in time, showing Kleban's interactions with friends and colleagues through his music.

Why it's essential: Just as A Chorus Line — for which Kleban wrote the lyrics — offered invaluable insight into the lives of performers, A Class Act is an intimate and revelatory peek behind the curtain. It's a fascinating study of how an artist's personal life interferes with his work — and vice versa.

What it's about:Memphis is inspired by the story of Dewey Phillips, who was one of the first white DJs to play black music in the '50s. Here, Dewey is reimagined as Huey, who enters the world of underground black clubs in Memphis because he loves the music, and ends up falling for Felicia, against societal conventions.

Why it's important: While Memphis isn't the first musical to cover similar subject matter, it still offers a different and important take on the relationship between racial segregation and rock 'n' roll. What makes the show especially effective is that the music, while recalling the era, is all original to the musical.

34.If/Then

Joan Marcus

Book: Brian Yorkey

Music: Tom Kitt

Lyrics: Brian Yorkey

Original Broadway cast: Idina Menzel as Elizabeth, LaChanze as Kate, Anthony Rapp as Lucas, James Snyder as Josh, Jenn Colella as Anne, Jerry Dixon as Stephen, Jason Tam as David

Performance dates: March 30, 2014-

What it's about: Recently divorced Elizabeth imagines two different paths for herself based on a chance decision — does she go with Kate or Lucas? The show explores both timelines, in which Elizabeth is alternately Liz and Beth, and how her relationships with Kate, Lucas, and a soldier named Josh play out differently.

Why it's essential: Some have criticized If/Then for being messy, but the show's intricate, complicated nature is the perfect representation of Elizabeth's life. The dual lives format is a fantastical conceit that's also grounded in reality, which makes for some heartbreaking moments in a musical that is ultimately life-affirming.

What it's about: This is what happens when you scramble to write a musical. Hunter Bell and Jeff Bowen based [title on show] on... well, writing [title of show]. It's a musical about the creation of a musical, inspired by the conversations they had as they were struggling to write a new original work.

Why it's essential: Few shows capture the artistic process better than [title of show], which is the definition of a happy accident. Yes, it's meta and post-modern, but it's also just a wonderful musical in its own right. It's an example of creative people getting together to make something new, and stumbling on genius.

What it's about: In documentary style, Jersey Boys tracks the rise and fall of 1960s rock band the Four Seasons, from their formation and subsequent fame to their eventual break-up. With music by the group, the show covers high points and low points, with band members directly addressing the audience at key moments.

Why it's essential: The jukebox musical gets a bad name, and sometimes that's warranted — as audiences yearn for more originality on Broadway, it can be disheartening to see shows with recycled music. But Jersey Boys perfected the form. Its structure and stellar performances make it the clear standout of the genre.

What it's about: Based on the novel of the same name by Alice Walker, The Color Purple follows sisters Celie and Nettie over the course of four decades in rural Georgia at the first half of the 20th century. Forcefully separated and kept apart, Celie and Nettie struggle to reunite and survive their circumstances.

Why it's essential: As when the novel The Color Purple was released in 1982, the themes of the musical remain timeless. The shocking depictions of racism and sexism perpetuated against the subjugated sisters are harrowing but necessary, and the overall experience is aided by a gorgeous score that made LaChanze a star.

What it's about: The first act of Grey Gardens shows Little Edie and Big Edie when they were younger and rich, before their lives fell into disrepair. The second act is based on the classic documentary Grey Gardens, in which an older Little Edie and Big Edie live an isolated existence in a dilapidated mansion.

Why it's essential: Another musical based on a movie, Grey Gardens significantly expands on the 1975 documentary by offering an imagined glimpse at life for its protagonists before everything went to shit. It makes the more familiar second act all the more heart-rending, creating valuable context where once there was none.

What it's about: As in the 2000 film, Billy Elliot finds himself more drawn to ballet than to wrestling — against his father's wishes. But Billy finds solace in dance and lessons from Mrs. Wilkinson, even as the world around him is in turmoil. The musical takes place during the U.K. coal miners' strike that lasted from 1984 to 1985.

Why it's essential: Cute kids aren't always what you want to see front and center in a musical, but the tremendous dancing by the young actors of Billy Elliot transcends any doubts even the most curmudgeonly audience members might have. And the show's concerns about masculinity, which should be dated, are still contentious.

What it's about: Part rock musical, part history, Bloody Bloody Andrew Jackson is about the founding of the Democratic Party in 1828. The show covers the eponymous U.S. president's life and work, in particular the rise of populism, the Indian Removal Act, and Jackson's relationship with his wife Rachel.

Why it's essential: Like other rock musicals, Bloody Bloody Andrew Jackson is relentlessly energetic, which only underscores the serious issues it addresses. Despite the fact that its politics are firmly rooted in the 1800s, they're relevant to a modern-day populace, a stirring reminder that the more things change...

What it's about: Based on the 1992 Disney film — and the true events that inspired it — Newsies is about the titular young men, largely orphaned and homeless, who hock newspapers on the street. When the price of papers is raised 10 cents by the greedy Joseph Pulitzer, Jack inspires his fellow newsies to protest.

Why it's essential: Say what you will about the Disney musical — Newsies shows what Disney gets right. The inspiring story and infectious music is as delightful here as it was in the original film, appealing to young audience members and the young at heart, like any good Disney production should.

What it's about: In 1959 Boston, the untalented star of Robbin' Hood of the Old West is murdered during the opening night curtain call. Enter Lieutenant Cioffi, who in addition to his detective skills is also a fan of musical theater. Cioffi has to solve the case and save the show, and he's got a murderer on his tail.

Why it's essential:Curtains may not be up there with Chicago and Cabaret, Kander and Ebb's most famous works, but it's an engaging and hilarious mystery that perfectly satirizes a very specific genre, the backstage murder mystery. More than that, it's also a love letter to classic musical theater.

What it's about: In 1965, disaffected housewife Francesca contemplates her life in Iowa, far away from her home in Italy. With her husband and kids away at the State Fair, Francesca meets National Geographic photographer Robert Kincaid, and the two embark on a passionate but short-lived affair that ends in heartbreak.

Why it's essential: The fact that The Bridges of Madison County didn't earn a Tony nomination for Best Musical is a travesty, made all the more tragic because the show was forced to close early. It's a beautiful, haunting show, with a rich score by Jason Robert Brown, and stunning performances by Kelli O'Hara and Steven Pasquale.

What it's about: In the dark world of Urinetown, a 20-year drought has made private toilets a thing of the past. Now all bathrooms are public and controlled by a megacorporation, which forces people to pay for the privilege of peeing. Charismatic Bobby Strong leads his fellow citizens in a revolution — with mixed results.

Why it's essential: Part of what makes Urinetown such a funny show is how unexpected it is. The musical repeatedly subverts expectations to darkly comedic effect, parodying far more serious works like Les Misérables and reminding audiences that not all musical comedy has a happy ending.

What it's about: Adapted by Mel Brooks from his 1968 film, the titular producers are Max Bialystock and Leo Bloom, who conspire to dupe investors by purposely making a Broadway flop. Their plan backfires when Springtime for Hitler, despite being an offensive disaster on paper, is celebrated as a hilarious comedy.

Why it's essential: Despite being based on a 30-year-old film, The Producers breathed new life into musical comedy. The book is sharp and relentlessly entertaining, but it's also full of great musical numbers, "Springtime for Hitler" being the obvious standout. The Producers paved the way for more great shows like it.

What it's about: In this musical based on the Giuseppe Verdi opera, Radames, who is next in line to become Pharaoh, falls for a captured Nubian slave named Aida, who is secretly a princess. Their forbidden love is complicated by Radames' intended bride Amneris and Aida's true identity, culminating in a tragic ending to their affair.

Why it's essential: It's hard to imagine that Aida was once intended to be adapted as a Disney film — the elements are still there (Elton John and Tim Rice), but it's a heavy, depressing love story. In addition to its undeniable power, Aida is significant for the way it blurs the lines between musical and opera.

What it's about: The unnamed Youth, a black man from South Central Los Angeles, rebels against his mother and his religious upbringing. He embarks on a journey to find "the real," traveling across Europe and exploring different genres of music, including rock, jazz, gospel, and punk, in order to find himself.

Why it's essential: Like other great rock musicals, the thrill of Passing Strange is that its creator Stew had no theatrical background. The result is something truly original, informed not by other musicals but by Stew's background as a rock 'n' roll performer. This is a rare reflection of a thoroughly unique new voice.

What it's about: In the '70s, Fela Kuti was an influential performer and composer in Nigeria. The musical is based on real events, when government soldiers were assigned to end Fela's public performances at the Shrine nightclub. Fela becomes involved with opposition, balancing his quest for fame and his desire for civil rights.

Why it's essential: Calling Fela! a jukebox musical feels misleading — yes, the music here comes from the work of the show's subject, Fela Kuti. But the appeal of Fela! is in its breathless, colorful performances — so intensely physical that two actors played the eponymous musician and alternated performances.

What it's about: Based on the 1928 narrative poem, The Wild Party is presented as a series of vaudeville sketches reflecting the setting, a swinging '20s party hosted by Queenie and Burrs, whose relationship is collapsing. The eclectic cast of characters include a fading star, a black prizefighter, a morphine addict, and a gay couple.

Why it's essential: Timing for The Wild Party was a little odd — there's another Wild Party musical, based on the same narrative poem, that emerged off-Broadway during the same season. Fans of both continue to debate which is better, but LaChiusa's offers a richer cast of characters and steamy interactions.

What it's about: In this autobiographical musical first conceived as a one-man show, Jon approaches his 30th birthday with anxiety over his failure to succeed as a composer. Meanwhile, he struggles with commitment to his girlfriend Susan, who wants a more stable life, and Jon's best friend Michael learns that he's HIV-positive.

Why it's essential: While not the instant classic that Rent was, Jonathan Larson's other major work is a far more personal look at the struggles that led him to write the iconic 1994 musical. The knowledge that Larson died before he could see the extent of his success adds another level of melancholy to Tick, Tick... Boom!

What it's about: In the Dominican-American neighborhood of Washington Heights in New York City, Usnavi, the owner of a small bodega, narrates the events happening around him. The cast of characters include matriarch Abuela Claudia, Usnavi's love interest Vanessa, recent Stanford drop-out Nina, and gringo Benny.

Why it's essential: Before In the Heights, musical theater hadn't dived into the Dominican-American cultural experience. This is a story about people who don't often see themselves represented on stage (or on film and TV, for that matter), and the music — rap and salsa — is long overdue for a Broadway presence.

What it's about: As in the 1988 John Waters film, Hairspray is about Tracy Turnblad, an overweight teenager who dreams of dancing on The Corny Collins Show and win the heart of Link Larkin in 1962 Baltimore. When she does finally make it onto the show, she shakes things up by taking a stand for racial integration.

Why it's essential: John Waters on Broadway could have gone a lot of ways, but Hairspray is pretty darn wholesome — Pink Flamingos this is not. And yet, it's just the right amount of edgy mixed with bubble-gum colors and tunes that evoke the best of '60s pop music. Harvey Fierstein's Edna remains one of his finest performances.

What it's about: What began as a concept album became a rock musical, detailing the life of Imelda Marcos, the former First Lady of the Philippines — from her early life, raised by Estrella Cumpas, to her career as a singer and model, and finally to the moment she and her family were forced to leave the country.

Why it's essential: Some of the best theatrical experiences are the oddest on paper. The parts of Here Lies Love are strange: It began as a concept album, it's about Imelda Marcos, Fatboy Slim is involved. But it all comes together to create a breathtaking, immersive production helmed by the incomparable Alex Timbers.

What it's about: Based on Alison Bechdel's autobiographical graphic novel, Fun Home explores Alison's relationship with her father Bruce over the years. Presented in non-linear format, the show covers Alison's discovery of her sexuality and coming out, as well as her father's hidden sexuality and eventual suicide.

Why it's essential: Like the graphic novel on which it's based, Fun Home is a heartbreaking musical. Even those who have criticized elements of the show acknowledge its impressive emotional core and the effect it has had on audiences. It was a highly personal story for Bechdel to share, and that intimacy remains.

What it's about:The Drowsy Chaperone is the name of the musical, but it's also the musical within the musical. The Man in the Chair, a Broadway enthusiast, plays one of his favorite records, The Drowsy Chaperone, and relives the classic (fake) 1920s musical comedy, complete with a wedding and gangsters in disguise.

Why it's essential: There are plenty of other self-referential musicals out there, but there's something truly special about The Drowsy Chaperone. The book is consistently clever, giving just enough insight into the agoraphobic Man in the Chair. The musical within the musical is both a perfect parody and delightful in its own right.

What it's about:The Full Monty is inspired by the 1997 film but Americanized — here, unemployed steelworkers in Buffalo decide to make money by performing a strip act. Because they're not as in shape as the Chippendales dancers their wives love, they decide to distinguish themselves by ending with full nudity.

Why it's essential: It's hard to believe that a musical about out-of-work (and out-of-shape) steelworkers who decide to become strippers would be as stirring and poignant as The Full Monty is. That's not to take away from the fun of the show, which is a given, but the real surprise is the gorgeous, emotionally honest score.

What it's about: Using the framework of a minstrel show, The Scottsboro Boys is based on the trial of nine black teenagers falsely accused of rape. The infamous trial was a miscarriage of justice, with the young men condemned to life in prison for a crime they didn't commit. The show is designed as a "musical social critique."

Why it's essential: The subject matter is undeniably important, and the unique format reflects musical theater's ability to be subversive with social commentary. This was also one of the last collaborations between Kander and Ebb before the latter's death. Alas, despite earning 12 Tony Awards nominations, it failed to win any.

What it's about: In this retelling of The Wizard of Oz, Elphaba — later known as the Wicked Witch of the West — gets to share her side of the story. She is shunned for her green skin, loathed by her college roommate Glinda, and ultimately hated and feared when she is forced to use her powers against the corrupt Wizard of Oz.

Why it's essential: One of the defining blockbuster musicals of the 2000s, Wicked has fans and detractors. But while it's not quite as cutting as the novel on which it's based, it's still one of the greatest modern musicals, drawing from classic musical theater tradition while embracing new innovations. Buzz aside, it's just that good.

What it's about: In a cave many miles to the south lives a boy born with fangs in his mouth. After being discovered, Bat Boy moves in with the Parker family, where he is soon civilized and falls in love with Shelly. But as deaths pile up in Hope Falls, the townspeople turn against Bat Boy — now Edgar — leading to a tragic conclusion.

Why it's essential: It's safe to say Bat Boy is the great musical inspired by a character from the Weekly World News. There is plenty of weirdness on display in this show — including a bizarre sequence in which the King of the Forest leads all the animals in copulation — but it's also sharp and sweet, with an addictive score.

What it's about: A parody of children's programs like Sesame Street, Avenue Q is educational for adults. It begins when Princeton moves to the depressingly bleak Avenue Q and meets his neighbors, most of whom are unemployed or miserable. Together they learn valuable lessons about racism, casual sex, and internet porn.

Why it's essential: The surprise Tony winner for Best Musical — it beat out Wicked — Avenue Q is so funny that it's easy to forget how much work the performers put into it. But these are talented puppeteers who had to invent a new form of stage presence. And they belt the songs, which are equal parts catchy and offensive.

What it's about: In 1963 Louisiana, Caroline is a maid for a Jewish family, the Gellmans. She has a special relationship with the young son Noah, whom she comforts in times of crisis. When Noah's stepmother can't give Caroline a raise, she suggests she take the change from Noah's pockets, which Caroline reluctantly does.

Why it's essential: Tony Kushner's talents as a playwright have long been celebrated, but Caroline, or Change is his first musical, and it's a stunner. The rich score, which combines Motown and blues with folk and klezmer, plays well against the heavy themes. Add to that stellar performances from the entire cast.

What it's about: The title says it all, really — a group of kids participate in the 25th annual Putnam County spelling bee. But despite being young (and exceedingly nerdy, for the most part), these children have complicated feelings and a rich internal life that plays out as they are eliminated, one by one, from the competition.

Why it's essential:Spelling Bee is that perfect blend of humor and heart. It never feels too serious or silly, and most of the time, it's just a lot of fun. But with music and lyrics by William Finn, who broke hearts with Falsettos, there are moments of genuine pathos. "The I Love You Song" may be the most beautiful he's ever written.

5.The Last Five Years

What it's about:The Last Five Years is a love story told backward and forward — the show documents the five-year relationship between novelist Jamie Wellerstein and actress Cathy Hyatt. Cathy's story is told in reverse, beginning at the end of the marriage, while Jamie's story is told chronologically, when the two met.

Why it's essential: Few composers can tell a love story like Jason Robert Brown. (See The Bridges of Madison County.) The Last Five Years feels intensely personal, because it was inspired by Brown's real-life failed marriage to Theresa O'Neill. Despite the non-linear style, it's a simple show that lets the score do the work.

What it's about: Two Mormon missionaries, charismatic Elder Price and hapless Elder Cunningham, are sent to a remote village in northern Uganda. They try to share the message of Mormonism, but are shocked by the realities they encounter — war, famine, and AIDS — so Elder Cunningham gets creative (makes shit up).

Why it's essential: Much as Mel Brooks turned out to be the unlikely candidate to reinvigorate musical comedy, South Park creators Matt Stone and Trey Parker shocked Broadway with a musical that's irreverent, offensive, and just plain great. It's not always PC, but its heart is in the right place — and more to the point, it's hilarious.

Why it's essential: In some ways, The Light in the Piazza is a traditional love story, but the show is actually far more complex than it lets on. This is a lush, sophisticated musical with some of the most gorgeous music written for the stage. It helps that stars Victoria Clark and Kelli O'Hara were at the top of their games: Both are perfect.

What it's about: Based on the 1891 German play of the same name, Spring Awakening follows the sexual awakening of a group of teenagers. Melchior and Wendla find themselves drawn to one another, unsure of what to do with their attraction, while their friend Moritz struggles with confusing desires and depression.

Why it's essential: There's a reason Spring Awakening launched the careers of Jonathan Groff and Lea Michele, among others. It's an amazing showcase for young talent, allowing its actors to get lost in roles that feel as relevant now as they were at the turn of the century. The phenomenal rock score also grounds it in the present.

What it's about: Diana is a mother struggling with bipolar disorder and depression, as evidenced by hallucinations of her long-dead son Gabe. Over the course of Next to Normal, she seeks treatment to help her survive, while her husband Dan and daughter Natalie struggle for some semblance of normalcy in their lives.

Why it's essential: No musical before Next to Normal had depicted mental illness with more accuracy and sympathy. This is a powerhouse of a show — anchored by incredible performances led by the brave, unflinching Alice Ripley — that leaves a lasting impression on everyone who sees it. Musicals have rarely been better.

A few notes: In order to be considered for inclusion, a musical had to have premiered on Broadway or off-Broadway on or after Jan. 1, 2000. Some shows on this list had workshops and out-of-town tryouts prior to the cut-off date, but they were included based on their New York debut. For shows that began off-Broadway but moved to Broadway, cast information is taken from the Broadway production. Finally, while the photos are from the original productions whenever possible, some have been taken from subsequent productions.